The Micro-Electro-Mechanical Systems, or MEMS, refers to a miniaturized mechanical and electro-mechanical member (i.e., devices and structures) that are made using the techniques of microfabrication. A MEMS microphone is a microphone which is based on MEMS technology. In the prior art, most MEMS microphones are condenser microphone.
Recently, piezoelectric MEMS microphone has been proposed. For example, a high performance piezoelectric MEMS microphone was proposed in the article of Robert John Littrell, et al, “High Performance Piezoelectric MEMS Microphones”, Ph.D. dissertation, Univ. Michigan, 2010, which is hereby incorporated herein by reference.
In the piezoelectric MEMS microphone of the prior art, the piezoelectric thin films for cantilever diaphragms do not have a base structure. Thus, a stress/stress gradient will cause a diaphragm curvature of the cantilever diaphragm. As a result, the acoustic performance and/or manufacturability will be impacted. Furthermore, the cantilever diaphragms are fragile and are not robust. Consequently, the manufacturing yield is low and operation is not reliable.
Therefore, there is a demand in the art that a new MEMS microphone shall be proposed to address at least one of the problems in the prior art.